Medications for Acromegaly
Medications can be used to treat acromegaly—a growth hormone disorder when the body produces too much growth hormone (GH). Your doctor may refer to this as "medical therapy," and generally, medications are prescribed if surgery doesn't entirely alleviate the symptoms of acromegaly.
You may also be prescribed medications before surgery if you have a particularly large pituitary tumor that's over-producing GH; the medications may shrink the tumor to make surgery more successful.
There are 3 medications used to treat acromegaly: somatostatin analogs (SSAs), growth hormone receptor antagonists (GHRAs), and dopamine agonists. This article will cover all 3, including possible side effects and who may benefit from the medication.
Somatostatin Analogs (SSAs)
Somatostatin analogs are synthetic (man-made) versions of the body's natural hormone somatostatin. Somatostatin is also known as growth hormone-inhibiting hormone (GHIH), so when it's released, it stops the production of GH.
SSAs aim to control production of GH, and they're usually the first medication tried for people with acromegaly who still have symptoms after surgery.
If you had surgery and your GH and insulin growth-factor 1 (IGF-1) levels are still too high, your doctor may have you try SSAs. Most patients find that they do lower GH levels, in addition to lowering IGF-1 levels.
Somatostatin analogs are usually injected into the muscles (an intramuscular injection) once a month. Your doctor will determine how much you get injected, but typical doses are between 10 mg and 30 mg.
Possible side effects: Some people taking SSAs develop certain side effects, but usually these aren't severe, and they don't last long. The most common side effects are diarrhea, gas, and nausea.
Who may try this acromegaly medication: SSAs can be used by acromegaly patients who've already had surgery but still have elevated GH and IGF-1 levels. They may also be used by patients who don't want surgery but still need to be treated for acromegaly.
Growth Hormone Receptor Antagonists (GHRAs)
Growth hormone receptor antagonists are another medication used to treat acromegaly. They work by blocking GH from doing one of its jobs—making IGF-1.
GH has to bond with certain receptors (GH receptors) in cells in order to produce IGF-1. GHRAs bond with GH receptors—and therefore prevent GH from bonding with them. You can think of it this way: GHRA competes with GH for the GH receptor slots. And if GH doesn't beat the GHRA to the GH receptors, then no IGF-1 is produced.
GHRAs lower the IGF-1 levels in people with acromegaly. Since it's IGF-1 that causes a lot of the tissue overgrowth associated with acromegaly, lowering IGF-1 levels should stop the excess growth. GHRA may also reduce the symptoms associated with acromegaly.
Growth hormone receptor antagonists are usually injected once a day, and the doses range from 10 mg to 40 mg. Your doctor will recommend the best dose for you.
Possible side effects: As with any medication, there are possible side effects associated with GHRAs. The most common side effects are headaches and fatigue. Some patients also experience liver function problems.
Who may try this acromegaly medication: If you've had surgery and your GH and IGF-1 levels didn't become normal, you may try growth hormone receptor antagonists. This medication is usually tried after somatostatin analogs. If SSAs don't work for you, then the doctor may suggest GHRAs. Additionally, patients with very high IGF-1 levels (more than 900 ng/mL) may try a GHRA.
The third medication typically used for acromegaly, dopamine agonists, doesn't tend to work for as many people as the other 2 medications listed. However, for certain patients, dopamine agonists may be the best choice.
Dopamine agonists work by preventing the release of GH from the pituitary tumor. It is taken once a week as a pill, and the dose ranges from 1 mg to 4 mg. Again, your doctor will determine the correct dose for you.
Possible side effects: People taking dopamine agonists may experience lightheadedness, headaches, or nausea.
Who may try this acromegaly medication: Dopamine agonists are more effective in people with pituitary tumors that make prolactin (another hormone), in addition to growth hormone. Patients who are using SSAs may use dopamine agonists at the same time, if their doctor believes it's necessary.
Acromegaly Medications Conclusion
There are 3 medications typically used to treat acromegaly: somatostatin analogs (SSAs), growth hormone receptor antagonists (GHRAs), and dopamine agonists. Your doctor will help determine which medication is right for you, taking into account your hormone levels, how successful your surgery was (if you had surgery), and overall acromegaly treatment goals.